In the art of processing saturated liquids, such as liquid petroleum gas (LPG), there are considerable problems with filtering it. The main problem is preventing portions of the LPG in liquid phase being filtered from changing its state from liquid phase to vapor phase. When this change of state takes place it results in vapor bubbles being formed which mix with the liquid phase. The change of state is due to the throttling effect of filtration on the LPG flow.
During the development of LPG throttle body fuel injection systems, this problem of filtering was experienced. It was found that in order to overcome this problem, a high capacity, low restriction fuel filter was needed. So, a filter was designed to hold large quantities of dirt and debris which normally contaminate LPG and the filter had a low flow impedance to minimize the formation of vapor bubbles in the filter. It was also found that if the filter was disposed near a means which would provide some level of refrigeration to the LPG flowing through the filter, there was a decrease in the tendency of the LPG, to change state (phase).
The problems resulting from the formation of vapor bubbles in the liquid phase of LPG are not only experienced in the filter, but in pumping and/or metering mechanisms down stream from the filter.
The vapor bubbles in saturated liquids being pumped create a high risk of cavitation damage to the pump due to the collapse of the vapor bubbles in the pump. It is only when vapor bubbles are prevented from forming that subsequent metering problems or vapor bubble collapse in the pumping mechanism and resulting cavitation damage are prevented.
The present invention overcomes these problems.